Nauwelaerts Sandra, Aerts Peter, Clayton Hilary
Functional Morphology Laboratory, Department of Biology, University of Antwerp, Wilrijk, Belgium; McPhail Equine Performance Center, Michigan State University, East Lansing, MI, USA.
Functional Morphology Laboratory, Department of Biology, University of Antwerp, Wilrijk, Belgium.
Vet J. 2013 Dec;198 Suppl 1:e59-64. doi: 10.1016/j.tvjl.2013.09.034. Epub 2013 Sep 26.
Spontaneous transitions from anti-phase to in-phase manual coordination are explained in the Haken model that describes the two preferred states as stable regions that work as attractors in a stability landscape. Switching between states coincides with a temporary loss of stability. Coordination variability is believed to be indicative of such a loss of stability. In this study, the hypothesis was tested that an increase in variability in the angle profiles of the joints responsible for the transition will precede the transition. A full gait analysis of four miniature horses transitioning from trot to canter was performed. Joint angle profiles were determined for the joints of all four limbs and were time-normalised to stride duration. Per horse and per stride, the coefficient of variance was calculated as the mean standard deviation of the joint profile over all trials divided by the mean joint angle × 100. As hypothesised, the most proximal limb joints (hip, scapulothoracic, shoulder) followed the predictions to a large extent. The variability of the hip joint angle of the trailing hind limb showed a peak of variability at stride 0; this was quickly reduced after the transition was completed. The detection of this brief perturbation in the hip joint indicates the importance of this joint in the transition process. The hip joint is related to the movements of the limb, pelvis and back, which is one of the main differences between symmetrical and asymmetrical gaits.
在哈肯模型中解释了从反相到同相手动协调的自发转变，该模型将两种偏好状态描述为稳定区域，在稳定性景观中起吸引子的作用。状态之间的切换与稳定性的暂时丧失相吻合。协调性变异性被认为是这种稳定性丧失的指标。在本研究中，对以下假设进行了测试：负责转变的关节角度轮廓变异性增加将先于转变发生。对四匹微型马从快步转变为跑步进行了全面的步态分析。确定了所有四条腿关节的关节角度轮廓，并将其时间标准化为步幅持续时间。每匹马和每一步，方差系数计算为所有试验中关节轮廓的平均标准差除以平均关节角度×100。如假设的那样，最接近身体近端的肢体关节（髋关节、肩胛胸廓关节、肩关节）在很大程度上符合预测。后肢拖曳侧髋关节角度的变异性在第0步时显示出变异性峰值；转变完成后迅速降低。检测到髋关节的这种短暂扰动表明该关节在转变过程中的重要性。髋关节与肢体、骨盆和背部的运动有关，这是对称步态和不对称步态之间的主要区别之一。
